Apparatus for manufacturing bags



Aug. 30, 1955 R. J. WILLIAMS ET AL 2,716,372

APPARATUS FOR MANUFACTURING BAGS Filed June 50, 1954 6 Sheets-Sheet l FIG. 2.

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APPARATUS FOR MANUFACTURING BAGS Filed June 50, 1954 6 Sheets-Sheet 3 FIG.4.

Aug. 30, 1955 R. J. WILLIAMS ET AL I 2,716,372

APPARATUS FOR MANUFACTURING BAGS Filed June 30, 1954 6 Sheets-Sheet 4 FIGS 25 Aug. 30, 1955 R. J. WILLIAMS ET AL 2,716,372

APPARATUS FOR MANUFACTURING BAGS Filed June 30, 1954 6 Sheets-Sheet 5 FIG 8 13/ Aug.- 30, 1955 R J WILLIAMS ET AL 2,716,372

APPARATUS FOR MANUFACTURING BAGS Filed June 30, 1954 6 Sheets-Sheet 6 I|llll|l United States Patent() 2,716,372 APPARATUS FOR MANUFACTURING BAGS Russell J. Williams, Clayton, and Milton J. Heimos, Lemay, Mo., assignors to Bemis Bro. Bag Company,

1. Louis, Mo., a corporation of Missouri Application June 30, 1954, Serial No. 440,468

14 Claims. (Cl. 93-30) This invention relates to apparatus for manufacturing bags, and more particularly to a bottomer for forming self-opening square bottoms (5. O. S. bottoms) on gusseted paper bags.

Among the several objects of the invention may be noted the provision of a bottomer of the class'described which is suitable for operations on individual lengths of gusseted bag tubing; the provision of a bottomer of this class'which is adapted to operate on tubing of different widths and different gusset sizes; the provision of a bottomer of this class which, when set up to operate on a run of a given size of bags, automatically compensates for variations from mean bag dimensions as frequently occur; and the provision of a bottomer of this class which is adjustable to obtain proper folding back of the bottom flaps for different sizes of bags. Other objects and features will be in part apparent and in part pointed out hereinafter.

The invention accordingly comprises the constructions hereinafter described, the scope of the invention being indicated in the following claims.

In the accompanying drawings, in which one of various possible embodiments of the invention is illustrated,

Fig. 1 is a plan view of an apparatus constructed in accordance with .this invention, showing a length of gusseted bag tubing being bottomed, parts of the tubing being broken away;

Fig. 2 is an enlarged fragment of Fig. 1, showing the tubing after opening up of the bottom;

Fig. 3 is a plan of the apparatus with a table top thereof removed;

Fig. 4 is a vertical section taken on line 44 of Fig. 5;

Fig. 5 is an end view of Fig. 4 as viewed from the left;

Fig. 6 is an enlarged vertical section taken on line 66 of Fig. 4;

Fig. 7 is an enlarged vertical section taken on line 7-7 of Fig. 8;

Fig. 8 is an enlarged fragment of Fig. 3, with parts shown in section;

Fig. 9 is a vertical cross section taken on line 99 of Fig. 6; and,

Fig. 10 is a diagram showing the air and electrical systems of the apparatus.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

Referring to the drawings, a bottomer constructed in accordance with this invention is shown to comprise a bed generally designated 1 having end frames 3 supporting horizontal front and rear bars 5 and 7, respectively. Extending upward from bars 5 and 7 are front and rear legs 9 and 11, respectively. Fixed to the upper ends of the legs are upper front and rear bars 13 and 15, respectively. Bars 13 and 15 support a table top 17. Extending between the front and rear bars 5 and 7 are bars 19 supporting front and rear rails 21 and 23, respectively. These'rails support a left-hand bottomer unit designated 2,716,372 Patented Aug. 30, 1955 ice in its entirety by reference character 25 and a right-hand bottomer unit designated in its entirety by reference character 27. These units 25 and 27' are of corresponding left and right-hand construction, and have corresponding parts which are identified by the same reference characters.

As shown, each of units 25 and 27 comprises a base plate 29 clamped by members 31 to supports mounted on the rails 21 and 23. The supports for unit 25 are designated 32; the supports for the unit 27 are designated 33. Supports 32 for unit 25 are secured to the rails at the left end of the bed by screws 34. Supports 33 for the right-hand unit 27 are releasably clamped to the rails 21 and .23 by members 35. By loosening members 35, unit 27 may be moved laterally inward or outward on the rails for changing the bottomer to operate on bags of different widths. Fixed on the base plate 29 of each of units 25 and 27 are spaced parallel vertical bearing plates 37 and 39. These extend from front to rear. A spacer block for the plates is indicated at 41. Each of units 25 and 27 has a gripper generally designated 43 for gripping the lower folds of the gussets of a length of gnsseted bag tubing. As to each of the units, the gripper 43 is mounted for inward and outward lateral movement andfor forward and rearward swinging movement,

being biased laterally outward and forward by a spring 45. Gripper 43 (see particularly Figs. 6 and 9) comprises a carriage consisting of a rectangular yoke 47 having lateral trunnions 48 and 49 which are rotary and axially slidable in bearings 51 and 53 in the bearing plates 37 and 39. The yoke has an upwardly projecting jaw 55 which extends into an opening 57 in the table top 17. The upper end face 59 of jaw 55 is generally flush with the top surface of 17 (see Figs. 4 and 9). A rod 61 is slidable in bearings 63 and 65 in the top and bottom of the yoke. This rod is located laterally outward from the jaw 55. At the upper end of the rod is a head 67 carrying an inwardly extending jaw 69 which reaches over and which is cooperable with the upper end face 59 of the jaw 55. A spring 71 surrounding therod reacts from the top of the yoke against a collar 73 on the rod to bias jaw 69 toward jaw 55. v A shaft 75 is journaled in bearings 77 and 79 carried by the bearing plates 37 and 39. Fixed onthe outer end of this shaft is a sector 81 carrying a cam 83. This cam is engageable with a follower roll 84 on a rocker'a'rm 85 pivoted at 87 on the outside of the outside plate 37 and engageable with the end of trunnion 48. Fixed on the inner-end of shaft 75 is a cam 89 engageable with a follower roll 90 on a rocker arm 91 pivoted at 93 on the inside of the inside plate 39 and engageable'with the end of trunnion 49. The rocker arms 85 and 91 are biased into engagement with the ends of the trunnions by a tena sion spring 94 connected between the arms. At 95 is shown an air cylinder for rotating the shaft 75. This is pivoted at 97 to a bracket 99 mounted on the base plate 29 and has its piston rod 101 pin-connected at 103 to the A journalled at its ends in the bearing plates 37 and 39. The

rocker arm 109 engages the lower end of rod 61. The previously mentioned spring 45 is a tension spring attached at one end as indicated at 113 to bar 115 angled laterally outward and forward from a top plate 117 mounted on plate 39. Plate 117 acts as a stop engageable by the yoke 47 to limit its forward swing under the bias of spring 45 see Fig. 6).

Each of units 25 and 27 has a gripper generally designated' 119 for gripping the upper folds of a length of gusseted bag. tubing. As to each of the units, the gripper 119 is mounted for inward and outward lateral movement and for swinging movement from a forward position overlying the respective lower fold gripper 43 to a rearward position for opening an S. O. S. bag bottom. Gripper 119 (see particularly Figs. 7 and 8) comprises a carriage or frame 121 fixed on a shaft 123 which is parallel to shaft and which is rotary and slidable in bearing openings 125 and 127 in a pair of vertical bearing plates 129 and 131. These plates are mounted on a platform 133 above the base plate 29. The axis of the shaft 123 is slightly above the surface of the table top 17. Platform 133 of unit 25 is supported on posts 135 extending upward from the outer support 32 of unit 25. Platform 133 of unit 27 is supported on posts 135 extending upward from the outer support 33 of unit 27. The carriage or frame 121 comprises inner and outer radial arms 137 and 139 secured together by a cross bar 141. Arm 137 is secured to the shaft 123 inward of the inside plate 129. Arm 139 is secured to the shaft 123 outward of the outside plate 131. The spacing of arms 137 and 139 is greater than the spacing of plates 129 and 131 so that the shaft 123 and the frame 121 may slide laterally inward and outward. The arms 137 and 139 have slots 143 and 145 receiving the ends of shaft 123. The arms are clamped to the shaft by means of clamp members 147 and clamp screws 149 threaded in the ends of the shaft. The frame 121 may be radially adjusted with respect to the shaft by loosening clamp screws 149.

Secured to the outer end of the inside arm 137 of frame 121 is a gripper jaw 151. A shaft 153 is journalled at its ends in openings 155 and 157 in the arms 137 and 139. Fixed on the inner end of the shaft 153 on the inside of the inside arm 137 is a gripper jaw 159 cooperable with the jaw 151. Jaw 159 extends generally radially from the shaft 153 over the jaw 151. A torsion spring 161 surrounding the shaft 153 has one end fixed to arm 139 as indicated at 163 and its other end fixed to a collar 165 on the shaft, and biases the shaft 153 in the direction to swing jaw 159 toward jaw 151. Arm 139 has an extension 167 on which is mounted an air cylinder 169 (see Fig. 5). The piston rod 171 of the air cylinder is engageable with a rocker arm 173 on the outer end of the shaft 153 for rotating the shaft against the bias of spring 161 forjawreleasing purposes.

Fixed on the shaft 123 of each of the units 25 and 27 between the plates 129 and 131 is a spur gear 175. As to each unit, the gear 175 is engaged by a wide-face spur gear 177 fixed on a shaft 179 journalled. in the plates 129 and 131. A platform 181 is mounted under the table top on posts 183 extending upward from the rails 21 and 23 between the ends of the apparatus. On the platform are front and rear bearings 185 and 187 (see Fig. 3) in which is journalled a shaft 189. This extends out from under the table top toward the front of the apparatus and has a crank 191 fixed on its forward end. Fixed on the rearward end of shaft 189 is a bevel gear 193 in mesh with a bevel gear 195 on a shaft 197 journalled in bearings 199 and 201 located toward the sides of the platform 181. Shaft 197 is aligned with the shafts 179 of units 25 and 27. Shafts 203 and 295 connect the ends of shaft 197 to shafts 179 of units 25 and 27. Suitable shaft couplings for connecting the shafts are indicated at 207. The arrangement is such that by turning handle 191, shafts 179 are rotated in unison, resulting in rotation of shafts 123 and frames 121 of both of the units 25 and 27. Shaft 205 is removable and replaceable by a shaft of different length upon adjustment of unit 27 for different widths of bags.

Means is provided for shifting the shafts 123 and frames 121 of both units 25 and 27 laterally in and out. As shown, this means for each unit comprises a rod 209 which is slidable in openings in the plates 129 and 131. Fixed on the rod between the plates is a shifter fork 215 straddling the gear 175 on shaft 123. Rod 209 with the fork 215 thereon is adapted to be shifted by an air cylinder 217 mounted on the platform 133. This platform is supported toward its inner end on a post 221 extending upward from for downward movement by spring 71.

a bar 223. The piston rod 225 of the air cylinder is connected at 227 to a rod 229 having spaced stop collars 231 and 233 thereon on opposite sides of a stop block 235 mounted on the platform 133. Rod 229 is coupled at 237 to the rod 209. Springs 239 and 241 connected between a bracket 242 fixed to plate 129 and a bar 243 carried by the piston rod 225 bias the piston rod and rods 229 and 209 outward.

Each unit 25 and 27 has a valve 245 for controlling the operation of its respective air cylinders 95 and 217 and a valve 247 for controlling the operation of its respective air cylinder 169 (see Figs. 3 and 10). As to each unit, valves 245 and 247 are mounted on a base plate 248 carried by the bar 223 (see Figs. 3 and 4). They are respectively actuated by cams 249 and 251 on a shaft 252 journaled in front and rear bearings 253 and 254 on base plate 248. Shaft 252 of each unit extends out from under the table top toward the front of the apparatus and has a handle 255 fixed on its forward end. The valve 245 of each unit is a two-way valve, having an inlet 255 supplied with compressed air from a suitable source (not shown) through a branch line 256 from a main line 257. It has a first port 259 connected by a line 260 to a line 261 leading to the rearward end of the respective cylinder 95 and to a line 263 leading to the outer end of the respective cylinder 217. Cylinder 217 is a one-way cylinder, having a vent 265 at its inner end. Valve 245 has a second port 267 connected by a line 269 to the forward end of the respective cylinder 95.

In its off position, valve 245 vents both the rearward end of cylinder 95 and the outer end of cylinder 217 via lines 261, 263, 260, port 259 and a vent port 271, and supplies air under pressure to the forward end of cylinder 95 via line 269. Under these circumstances, the piston in cylinder 95 is held in a rearward retracted position, and the piston in cylinder 217 is free. With the piston in cylinder 95 in the stated retracted position, the shaft 75 and earns 81, 89 and 105 thereon occupy an initial angular position. Cams 81 and 89 are so developed and phased that in their stated initial angular position they free the yoke 47 for laterally outward movement under the bias of spring 45, and spring 45 accordingly holds the yoke 47 in an outwardly retracted position adjacent the outer bearing plate 37. Cam 105 holds the rocker arm 109 raised and hence holds the rod 61 raised to hold the upper jaw 69 raised from the jaw 55. With the piston in cylinder 217 free, springs 239 and 241 hold the entire upper fold gripper 119 in an outwardly retracted position determined by engagement of stop collar 233 with the stop block 235.

When valve 245 is operated to its on position, it vents the forward end of cylinder 95 via line 269, and supplies air under pressure to both the rearward end of cylinder 95 and the outer end of cylinder 217 via lines 260, 261 and 263. With pressure in the rearward end of cylinder 95 and the forward end of cylinder 95 vented, the piston in the cylinder 95 is driven forward to rotate shaft 75 and cams 81, 89 and 105 thereon to an advanced position. Here the action of cams 81 and 89 is such that the yoke 47 is driven inward (toward the inner bearing plate 39), and when the cams reach their advanced position, the yoke is freed to be subject to the outward bias of spring 45. The action of cam 105 is such that when it reaches its advanced position, rod 61 is freed With pressure in the outer end of cylinder 217, the piston in the cylinder is moved inward to pull the entire upper fold gripper 119 inward to an inner operative position determined by engagement of the stop collar 231 with the stop block 235.

Valve 247 is a one-way valve having an inlet 273 supplied with air under pressure from the main line 257 through a line 275, and an outlet 279 connected by a line 281 to the lower end of cylinder 169. It also has a vent 283. In its off position, valve 247 vents the lower end of cylinder 169, allowing spring 161 to hold the jaw 159 open. In its on position, valve 245 supplies air under pressure to cylinder 169, thereby rock ing arm 173 and shaft 153 to close the jaw 159.

In the line 263 for one of the units or 27 (the righthand unit 27 as shown) is a solenoid valve 283. This valve, when deenergized, holds air under pressure in line 263 leading to the cylinder 217 for the right-hand unit. When energized, it vents the line 263 via a vent 284. Valve 283 is under control of a switch 285 in turn controlled by a cam 287 on shaft 197 (see Fig. 3). Wiring between the switch and valve is indicated at 289.

A table 291 is provided in the rear of the apparatus, its top constituting a rearward extension of the table top 17. The latter is provided with adjustable stops 293 for engagement by an end of a length of gusseted tubing B to be bottomed.

Operation is as follows:

Unit 27 is laterally adjusted (moved to the right or left, as required) to make the distance between the grippers 43 and 119 of the units 25 and 27 somewhat greater than the width of the lengths of tubing in a run to be bottomed when the grippers are in their outwardly retracted position. Base plates 29 of units 25 and 27 are adjusted forward or rearward as required to locate the lower fold grippers 43 at a distance from the axis of shafts 123 corresponding to the width of one gusset panel. This adjustment is carried out by loosening the clamp members 31. The stops 293 are adjusted forward or rearward as required so that the distance from the vertical plane of the axis of shafts 123 to the plane of the rearward faces of the stops corresponds to the desired distance from the end of the length of tubing to the line L on which the upper wall of the tubing is to be folded back to open up the S. O. S. bottom. The frames 121 of the upper fold grippers 119 of both units 25 and 27 are adjusted radially in relation to the respective shafts 123 to locate the upper fold gripper jaws 151 and 159 at a distance from the axis of shafts 123 corresponding to the width of one gusset panel.

A length of tubing is placed in position between the two units 25 and 27 with its forward end engaging the stops 293, being supported by the table top 17 and the table 291. With frames 121 in their forward position, the handles 255 are turned to operate the valves 245and 247. As valves 245 are turned on, the yokes 47 and the frames 121 are moved inward from their outward retracted position in such manner that the jaws 55 come under the tubing at opposite sides, jaws 69 and 151 reach into the gussets, and jaws 159 come over the tubing at opposite sides (see Fig. 4). When the yokes 47 reach their inner operative positions, rods 61 are freed for downward movement by the springs 71, and the lower folds of the gussets are thereby clamped between jaws 69 and the upper end faces 59 of jaws 55. When the frames 121 reach their inner operative position, valves 245 are turned on by cams 247, thereby effecting movement of the jaws 159 toward the jaws 151 to clamp the upper folds of the gussets. When the yokes 47 reach their inner operative position, they are freed for outward movement under the bias of springs 45, and, with the lower folds of the gussets clamped between the lower gripper jaws 69 and 55, the end of the tubing is stretched taut laterally.

After the upper and lower folds of the gussets at both sides of the tubing have been clamped as above described, the crank 191 is turned to rotate the shaft 197 in such direction as to effect swinging movement of the frames 121 from their forward position to a rearward position for opening up an S. O. S. bag bottom (see Fig. 2). As the crank 191 is turned, cam 287 on the shaft 197 operates switch 285 to energize the solenoid valve 283, thereby venting the line 263 to vent the cylinder 217 for the righthand unit. When this occurs, the springs 239 and 241. become operative to bias the frame 121 of the right-hand unit laterally outward, thereby laterally stretching taut the portion of the tubing extending between the closed pairs of jaws 151 and 159. Also, when the frames 121 are swung to their rearward position, the yokes 47 are swung rearward and springs act to stretch taut the sides 8' of the bottom.

After the bottom has been opened as described, the portion of the tubing forward of the lower pairs of jaws and 69 is folded over on the transverse line indicated at C in Fig. 2 and the portion of the folded-back section of the tubing rearward of the upper pairs of jaws 151 and 159 is folded forward on the transverse line indicated at D in Fig. 2, the folded-over flaps being pasted together to complete the bottom.

Following the above, the handles 255 are returned to their initial position to return thevalves 245 and 247 to their off position. This opens the pairs of jaws 55, 69 and 151, 159 and releases the yokes 47 and frames 121 for return outward to their retracted position. The bottomed bag is then removed, and crank 191 is turned to swing the frames 121 back to their forward position for another operation.

From the above, it will be seen that the lower fold grippers 43 (each including the paired jaws 55 and 69) are biased. laterally outward towarda retracted position outward of the sides of the tubing and also in the direction toward the endof the tubing to be bottomed by the springs 45. Means is provided for moving the lower fold grippers inward while their jaws are open, then closing the jaws to clamp the lower folds of the gussets, and then releasing the lower fold grippers to be biased laterally outward so as to stretch the lower wall of the tubing laterally. The upper fold grippers 119 (each including the paired jaws 151 and 159) are biased laterally outward toward a retracted position outward of the sides of the tubing. Means is provided for moving them inward while their jaws are open, then closing, the jaws to clamp the upper folds of the gussets, and then releasing at least-one of them to be biased laterally outward during the opening up of the bag bottom to stretch the upper wallof the tubing laterally. Whenthe apparatus has been set up to open up bottoms for tubing of given total width. and given gusset width, any variations from standard total width and gusset width as may occur are automatically compensated for by the ability of the apparatus to stretch the tubing laterally along the lines C and D where the front and back bottoming flaps are folded and along sides S.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter. contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

We claim:

1. Apparatus for opening a bottom at the end ofv a length of gusseted bag tubing, comprising a support, a pair of first grippers for gripping the lower folds ofthe gussets of the tubing at opposite sides of the tubing, s'aid first grippers being mounted on the support for lateral in.- ward and outward movement relative to the tubing and also for movement lengthwise of the tubing, means biasing said first grippers laterally outward toward a retracted position outward of the sides of the tubing and also biasing them in the direction toward said end of the tubing, means for moving said first grippers inward while open, then closing them to grip the lower folds of the gussets and releasing them to be biased laterally outward so as to stretch the lower wall of the tubing laterally, apair of second grippers for gripping the upper folds of the gussets at opposite sides of the tubing, said second grippers being mounted on the support for lateral. inward and outwardmovement relative to the tubing and also for swinging movement from aforward position 'in the direction away from said end of the tubing to a rearward position for opening a bottom, means biasing said second grippers laterally outward toward a retracted position outward of the sides of the tubing, means for moving said second grippers inward while open and then closing them to grip the upper folds of the gussets, means for then swinging the second grippers from their forward to their rearward position to open a bottom, and means for releasing at least one of said second grippers to be biased laterally outward during the swinging thereof to stretch the upper wall of the tubing laterally.

2. Apparatus for opening a bottom at the end of a length of gusseted bag tubing, comprising a support, two grippers each including means for clamping the lower folds of the gussets at opposite sides of the tubing, said lower fold grippers being mounted on the support for lateral inward and outward movement relative to the tubing and also for movement lengthwise of the tubing, means biasing said lower fold grippers laterally outward toward a retracted position outward of the sides of the tubing and also biasing them in the direction toward said end of the tubing, means for moving said first grippers inward with their clamping means open, then closing their clamping means to clamp the lower folds of the gussets, then releasing the grippersto be biased laterally outward while the clamping means remains clamped on the lower folds so as to stretch the lower wall of the tubing laterally, two grippers each including means for clamping the upper folds of the gussets at opposite sides of the tubing, said upper fold grippers being mounted on the support for lateral inward and outward movement relative to the tubing and also for swinging movement from a forward position in the direction away from said end of the tubing to a rearward position for opening a bottom, means biasing said upper fold grippers laterally outward toward a retracted position outward of the sides of the tubing, means for moving said upper fold grippers inward with their clamping means open, then closing their clamping means to grip the upper folds of the gussets, means for then swinging the upper fold grippers from their forward to their rearward position with their clamping means clamped on the upper folds to open a bottom, and means for releasing at least one of said upper fold grippers to be biased laterally outward during the swinging thereof while its clamping means remains clamped on the respective upper fold to stretch the upper wall of the tubing laterally. I

3. Apparatus for opening a bottom at the end of a length of gusseted bag tubing, comprising a support, two grippers each including a pair of relatively movable jaws for clamping the lower folds of the gussets at opposite sides of the tubing, said lower fold grippers being mounted on the support for lateral inward and out ward movement relative to the tubing and also for movement lengthwise of the tubing, means biasing said lower fold grippers laterally outward toward a retracted position outward of the sides of the tubing and also biasing them in the direction toward said end of the tubing, means for moving said first grippers inward with their jaws open, then closing their jaws to clamp the lower folds of the gussets, then releasing the grippers to be biased laterally outward while their jaws remain clamped on the lower folds so as to stretch the lower wall of the tubing laterally, two grippers each including a pair of relatively movable jaws for clamping the upper folds of the gussets at opposite sides of the tubing, said upper fold grippers being mounted on the support for lateral inward and outward movement relative to the tubing and also for swinging movement about a lateral axis from a forward position in the direction away from said end of the tubing to a rearward position for opening a bottom, said upper fold grippers also being mounted for adjustment of their jaws to different radii with respect to said lateral axis, means biasing said'upper fold grippers laterally outward toward a retracted position outward of the sides of the tubing, means for moving said upper fold grippers inward with their jaws open, then closing their jaws to clamp the upper folds of the gussets, means for then swinging the upper fold grippets from their forward to their rearward position with their jaws clamped on the upper folds to open a bottom, and means for releasing one of said upper fold grippers to be biased laterally outward during the swinging thereof while its jaws remain clamped on the respective upper fold to stretch the upper wall of the tubing laterally.

4. Apparatus for opening a bottom at the end of a length of gus'seted bag tubing, comprising a support, right and left-hand bottomer units toward the sides of the support, each of the bottomer units having a lower gusset fold gripper comprising a carriage mounted for inward and outward lateral sliding movement and for movement in forward and rearward direction, and a fixed jaw and a movable jaw on said carriage for clamping a lower gusset fold, means biasing the carriage to slide laterally outward to a retracted position wherein the jaws are outward of the sides of the tubing and also biasing the carriage for movement in forward direction, means for moving the carriages laterally inward with the jaws open, then closing the jaws to clamp the lower folds of the gussets, then releasing the carriages to be biased laterally outward while the jaws remain clamped on the lower folds, each of the bottomer units also having an upper gusset fold gripper comprising a carriage mounted for inward and outward lateral sliding movement and also mounted to swing on a lateral axis from a forward position to a rearward position for opening a bottom, and a fixed jaw and a movable jaw on said upper fold gripper carriage for clamping an upper gusset fold, means biasing the upper fold gripper carriages to slide laterally outward to a retracted position wherein their jaws are outward of the sides of the tubing, means for moving the upper fold gripper carriages inward with their jaws open and then closing their jaws to clamp the upper folds of the gussets, means for swinging the upper fold gripper carriages from their forward to their rearward position with their jaws clamped 0n the upper folds to open a bottom, and means for releasing one of said upper fold gripper carriages to be biased laterally outward during the swinging thereof while its jaws remain clamped on the respective upper fold.

5. Apparatus for opening a bottom at the end of a length of gusseted bag tubing, comprising a support, right and left-hand bottomer units toward the sides of the support, each of the bottomer units having a lower gusset fold gripper comprising a carriage mounted for inward and outward lateral sliding movement and for forward and rearward swinging movement on a lower lateral axis, and a fixed jaw and a movable jaw on said carriage for clamping a lower gusset fold, means biasing the carriage to slide laterally outward to a retracted position wherein the jaws are outward of the sides of the tubing and also biasing the carriage to swing in forward direction, means for moving the carriages laterally inward with the jaws open, then closing the jaws to clamp the lower folds of the gussets, then releasing the carriages to be biased laterally outward while the jaws remain clamped on the lower folds, each of the bottomer units also having an upper gusset fold gripper comprising a carriage mounted for inward and outward lateral sliding movement and also mounted to swing on an upper lateral axis from a forward position to a rearward position for opening a bottom, and a fixed jaw and a movable jaw on said upper fol-d gripper carriage for clamping an upper gusset fold, each upper fold gripper carriage being radially adjustable with respect to its said axis, means biasing the upper fold gripper carriages to slide laterally outward to a retracted position wherein their jaws are outward of the sides of the tubing, means for moving the upper fold gripper carriages inward with their jaws open and then closing their jaws to clamp the upper folds of the gussets, means for swinging the upper fold gripper carriages from their forward to their rearward position with their jaws clamped on the upper folds to open a bottom, and means for releasing one of said upper fold gripper carriages to be biased laterally outward during the swinging thereof while its jaws remain clamped on the respective upper fold.

6. Apparatus as set forth in claim wherein the mov- :able jaw on each lower fold gripper carriage is biased to- Ward the respective fixed jaw, and wherein means is provided for releasably holding the respective movable jaw in open position against the bias.

7. Apparatus as set forth in claim 5 wherein the means biasing each lower fold gripper carriage to slide outward and swing forward consists of a single tension spring :attached at one end to the carriage and at its other end to the support and angled laterally outward and forward with respect to the carriage. I

8. In apparatus for opening a bottom at the end of a length of gusseted bag tubing, a pair of spaced bearing plates, a carriage having trunnions which are rotary and :axially slidable in bearings in the plates, said carriage having a first jaw, a rod carrying a second jaw and carried by the carriage for movement of the second jaw toward and :away from the first jaw, a spring biasing the rod to move the second jaw toward the first jaw, a shaft journalled in rbearings in the plates, a cam on the shaft between the plates controlling the rod, a pair of cams on the shaft outward of the plates for axially shifting the carriage, a spring biasing the carriage to slide in one direction and 'to swing in one direction, and a stop for limiting the swing of the carriage.

9. In apparatus for opening a bottom at the end of a length of gusseted tubing, a pair of spaced bearing plates, :a first shaft which is rotary and axially slidable in the plates, a gear fixed on the first shaft between the plates, a second shaft journalled in the plates, a wide-face gear on the second shaft in mesh with the first-mentioned gear, the latter being axially slidable while remaining in mesh with the wide-face gear, a pair of arms extending radially from the first shaft outward of the plates and spaced apart a distance greater than the spacing of the plates, a jaw fixed on one of the arms, a third shaft rotary in the arms carrying a jaw cooperable with the fixed jaw, means for rotating the third shaft, means biasing said first shaft together with the arms thereon to slide in one direction, and means for sliding said first shaft together with the arms thereon in the opposite direction.

10. Apparatus as set forth in claim 9 wherein the means for rotating the third shaft comprises a spring biasing the third shaft to rotate in jaw-closing direction, and means carried by the other of the arms for rotating the third shaft in jaw-opening direction against the vbias.

11. Apparatus as set forth in claim 9 wherein the gigs are radially adjustable with respect to the first 10 12. Apparatus for opening a bottom at the end of a length of gusseted bag tubing, comprising a pair of first grippers for gripping the folds at opposite sides of one wall of the tubing, a pair of second grippers for gripping the folds at opposite sides of the other wall of the tubing, both pairs of grippers being mounted for lateral inward and outward movement relative to the tubing, means biasing both pairs of grippers laterally outward toward a retracted position outward of the sides of the tubing, means for moving both pairs of grippers laterally inward while open, then closing them to grip said folds and releasing at least one gripper of each pair to be biased laterally outward so as to stretch the walls of the tubing laterally, one of said pairs of grippers being mounted for swinging movement from a forward position in the direction away from said end of the tubing to a rearward position for opening a bottom, and one of said pairs of grippers also being mounted for movement in such direction as to stretch the sides of the opened bottom and being biased in such direction so as to stretch the sides of the opened bottom.

13. Apparatus for opening a bottom at the end of a length of gusseted bag tubing, comprising a pair of first grippers for gripping the folds at opposite sides of one wall of the tubing, a pair of second grippers for gripping the folds at opposite sides of the other wall of the tubing, both pairs of grippers being mounted for lateral inward and outward movement relative to the tubing, means biasing both pairs of grippers laterally outward toward a retracted position outward of the sides of the tubing, means for moving both pairs of grippers laterally inward while open, then closing them to grip said folds and releasing at least one gripper of each pair to be biased laterally outward so as to stretch the walls of the tubing laterally, one of said pairs of grippers being mounted for swinging movement on a lateral axis with respect to the tubing from a forward position in the direction away from said end of the tubing to a rearward position for opening a bottom, one of said pairs of grippers also being mounted for movement in such direction as to stretch the sides of the opened bottom and being biased in such direction as to stretch the sides of the opened bottom, said pairs of grippers being relatively adjustable longitudinally of the tubing to vary the distance between the lateral axis of the pair of swinging grippers and the other pair of grippers, and the pair of swinging grippers being radially adjustable to vary their distance from said axis.

14. Apparatus as set forth in claim 13 wherein the. grippers for gripping the folds at one side of the tubing are laterally adjustable relative to the grippers for grip; ping the folds at the other side of the tubing.

N0 s s sss ites: 

